Fabric bonding with thermoplastic fibrous mats

ABSTRACT

A method of bonding fabrics wherein a fibrous, thermoplastic adhesive is sprayed on the fabric and the bond is formed by heating the fabric and adhesive. The resulting seam or sprayed area is porous, flexible and has good hand.

United States Patent 1 Peerman et al.

FABRIC BONDING WITH THERMOPLASTIC FIBROUS MATS Inventors: Dwight E.Peerman, Minnetonka; Huibert van Demmeltraadt, Coon Rapids, both ofMinn.

Assignee: General Mills, Inc.

Fled: Feb. 5, 1970 Appl. No.: 9,036

References Cited UNITED STATES PATENTS 1 H1970 Brazdzionij ..156/279 X[451 Feb. 20, 1973 2,713,078 7/1955 Gros et a1. ..117/104 X 2,792,3265/1957 Doyle et al. ..117/104 A 3,330,713 7/1967 Watson et al ..156/2473,055,788 9/1962 Stanhope et al.. ..156/247 2,130,932 9/1938 Sipe..156/66 3,499,853 3/1970 Griebsch et a1. ..156/331 3,383,263 5/1968Storti ..156/235 3,629,027 12/1971 Germain.... .....156/l79 X 3,464,8769/1969 Barb ..156/155 3,496,042 2/1970 Wyness ct al..... .....l56/l55 X3,442,736 5/l969 Duns ..156/155 X Primary Examiner-Carl D. QuarforthAssistant ExaminerRoger S. Gaither Attorney-Anthony A. Juettner andJerome J. .lenko [57] ABSTRACT A method of bonding fabrics wherein afibrous, thermoplastic adhesive is sprayed on the fabric and the bond isformed by heating the fabric and adhesive. The resulting seam or sprayedarea is porous, flexible and has good hand.

6 Claims, N0 Drawings FABRIC BONDING WITH THERMOPLASTIC FIBROUS MATSThis invention relates to polymers which form a discontinuous, porousadhesive fibrous mat that can be successfully used in the bonding offabrics. More specifically, this invention relates to thermoplasticpolymers, preferably those derived from polymerized fatty acids,diamines, and other coacid monomers which can be used to form adiscontinuous, porous, adhesive, fibrous mat.

In the past, various polymers have been used to produce an adhesivesystem to bond together seams of clothing, and to bond zippers andlabels to garments. However, the polymer systems used in the past havehad some disadvantages since the bonding was often in the form of anadhesive film applied to the surfaces to be bonded. In addition to thelimitations inherent in a film adhesive, the attempted use of variouspolymers in fabric bondings have been found to be deficient in one ormore of the following:

1. insufficient bonding to the fabric,

2. difficult to use,

3. little resistance to dry cleaning or the hot detergents, bleaches, orhigh temperatures encountered in commercial laundries,

4. too rigid to be comfortable when worn next to the skin,

5. too dark in color or pick up an objectionable color duringlaundering,

6. lack of porosity in the seam to allow the seam to breathe.

The use of the prior art methods has seriously limited the'use ofadhesive systems on open face and open weave fabrics. As an example, theconventional adhesive systems are applied as a film to the surface of abase material, for instance the bonding in a womans slip. To apply alace applique to the slip, it would be necessary to first apply a filmto the tricot and then apply the lace over the adhesive film followed bysealing with heat. In this manner, the applique would be bonded to thesurface of the slip. However, the adhesive would show through the laceor applique openings as a very shiny surface. This property is definedherein as showthrough. showthrough, in delicate work such as theapplication of lace to a slip, is very undesirable. Likewise, to applythe lace via sewing is very time consuming since the lace pattern wouldhave to be followed to properly attach the lace to the slip. Similarly,when bonding open weave material, the adhesive passes through theopenings and appears as a shiny surface (showthrough). An open weavematerial in which showthrough would be a disadvantage is decoratorburlap.

These disadvantages can now be overcome by the use of the adhesivesystem described herein. The adhesive layer is a fibrous mat which isporous and discontinuous in nature. The mat can be placed between layersof fabric and then heat sealed by applying heat to the fabric. The termfabric as used herein is defined as materials made from natural fiberssuch as cotton, wool, linen, and the synthetic fibers such as nylon,polyester, or polyacrylic fibers, either alone or in mixtures with eachother. Thus the term as used herein indicates items having the nature ofcloth and items which are normally used where cloth is used, such asclothing, garments, and other wearing apparel and includes woven andso-called non-woven fabrics.

When practicing this invention, a discontinuous layer of adhesive isapplied to one of the surfaces to be bonded. Generally, slight pressureand various other means such as direct spraying of the adhesive orheating of the fabric to which the adhesive is to be applied, issufficient to attach the adhesive prior to completing the bondingprocess. The second fabric to be bonded may then be placed on theadhesive mat and heat applied to seal the seam.

When practicing this invention, one of the preferred embodimentsincludes the dissolution of a thermoplastic adhesive in a solvent. Thedissolved adhesive can be sprayed in the form of fibers to the surfaceof the fabric to be bonded. The sprayed fibers will adhere to thesurface of the fabric and any residual solvent will either evaporate orpass through any of the openings in the fabric. The fabric to be bondedto the sprayed fabric can then be placed over the sprayed adhesive andheat applied. The duration of the heat application depends upon thethermoplastic adhesive being used as well as the materials being bondedtogether. Generally, the temperature will be at least 200F. for aminimum of 5 seconds.

As indicated above, thermoplastic adhesives are used in this invention.Preferred thermoplastic adhesives are the polyamides and polyestersderived from polymerized fatty acids and other polyesters. Among themost successful polymers used as adhesives within the scope of thisinvention are the polymerized fatty acid polyamides which are thereaction product of polymerized fatty acids and diamines. The polymericfat acids which may be employed in preparing the polymers are thoseresulting from the polymerization of drying or semi-drying oils or thefree fat acids or simple alcohol esters of these fat acids. The term fatacids is intended to include saturated, ethylenically unsaturated andacetylenically unsaturated, naturally occurring, and any syntheticmonobasic aliphatic acids containing from 16 to 24 carbon atoms. Theterm polymeric fat acid refers to polymerized fat acids. The termpolymeric fat radical refers to the hydrocarbon radical of a polymerizedfat acid, and is generic to the divalent, trivalent, and otherpolyvalent hydrocarbon radicals of dimerized fat acids, trimerized fatacids and higher polymers of fat acids. The divalent and trivalenthydrocarbon radicals are referred to herein as dimeric fat radical andtrimeric fat radical respectively.

The saturated, ethylenically unsaturated, and acetylenically unsaturatedfat acids are generally polymerized by somewhat different techniques,but because of the functional similarity of the polymerization product,they are generally referred to as polymeric fat acids.

Saturated fat acids are difficult to polymerize but polymerization canbe obtained at elevated temperatures with a peroxidic catalyst such asditertiarybutyl peroxide. Because of the generally low yields ofpolymeric products, these materials are not currently commerciallysignificant. Suitable saturated fat acids include branched and straightacids such as caprylic acid, pelargonic acid, capric acid, lauric acid,myristic acid, palmitic acid, isopalmitic acid, stearic acid, arachidicacid, behenic acid, and lignoceric acid.

The ethylenically unsaturated acids are much more readily polymerized.Suitable polymerization methods are disclosed in U. S. Pat. No.3,256,304 and No. 3,157,681. The ethylenically unsaturated acids can bepolymerized using both catalytic or non-catalytic polymerizationtechniques.

The preferred aliphatic acids are the monoand polyolefinicallyunsaturated 18 carbon atom acids. Representative of such acids are4-octadecenoic, 5-octadecenoic, 6-octadecenoic (petroselinic),7-octadecenoic, S-octadecenoic, cis-9-octadecenoic (oleic),trans-9-octadecenoic (elaidic), ll-octadecenoic (vaccenic),l2-octadecenoic and the like. Representative octadecadienoic acids are9,12-octadecadienoic (linoleic 9,1 l-octadecadienoic,10,12-octadecadienoic, 12,15-octadecadienoic and the like.Representative octadecatrienoic acids are 9,l2,l5-octadecatrienoic(linolenic), 6,9,l2-octadecatrienoic, 9,1 1,13-octadecatrienoic(eleostearic), 10,1 2,14-octadecatrienoic (pseudo-eleostearic) and thelike. A representative 18 carbon atom acid having more than three doublebonds is moroctic acid with is indicated to be4,8,12,15-octadecatetraienoic acid. Representative of the less preferred(not as readily available commercially) acids are: 7-hexadecenoic,9hexadecenoic (palmitoleic), 9-eicosenoic (gadoleic), ll-eicosenoic,6,10,14-hexadecatrienoic (hiragonic), 4,8,12,16-eicosatetraenoic, 4,812,1 5 ,1 8-eicosapentanoic (timnodonic), l3-docosenoic (erucic),ll-docosenoic (cetoleic), and the like.

The polymerization of the described ethylenically unsaturated acidsyields relatively complex products which usually contain a predominantportion of dimerized acids, 3 smaller quantity of trimerized and higherpolymeric acids and some residual monomers. The dimerized acids,generally containing 32 to 44 carbon atoms can be obtained in reasonablyhigh purity from the polymerization products by vacuum distillation atlow pressures, solvent extraction, or other known separation procedures.It is preferred to have a dimer acid content of at least 80 percent,more preferably 90 percent. The polymerization product varies somewhatdepending on the starting fat acid or mixtures thereof and thepolymerization technique emplyed-i.e. thermal, catalytic, particularcatalyst, conditions of pressure, temperature, etc. Likewise, the natureof the dimerized acids separated from the polymerization product alsodepends somewhat on these factors although such acids are functionallysimilar.

As a practical matter, the dimeric fat acids are preferably prepared bythe polymerization of mixtures of acids (or the simple aliphatic alcoholestersi.e. methyl esters) derived from the naturally occurring dryingand semi-drying oils or similar materials. Suitable drying orsemi-drying oils include soybean, linseed, tung, perilla, oiticia,cottonseed, corn, sunflower, dehydrated castor oil and the like. Also,the most readily available acid is linoleic or mixtures of the same witholeic, linolenic and the like. Thus, it is preferred to use as thestarting materials, mixtures which are rich in linoleic acid. Anespecially preferred material is the mixture of acids obtained from talloil which mixture is composed of approximately 40-45 percent linoleicand 50-55 percent oleic.

Reference has been made hereinabove to the monomeric, dimeric andtrimeric fat acids present in the polymeric fat acids. The amounts ofmonomeric fat acids, often referred to as monomer, dimeric fat acids,often referred to as dimer, and trimeric or higher polymeric fat acids,often referred to as trimer, present in polymeric fat acids may bedetermined analytically by gas-liquid chromatography of thecorresponding methyl esters. Unless otherwise indicated herein, thisanalytical method was used in the analysis of the polymeric fat acidsemployed in this invention. Another method of determination is amicromolecular distillation analytical method. This method is that of R.F. Paschke et. al., J. Am. Oil Chem. Soc., XXXI (No. l), 5, (1954),wherein the distillation is carried out under high vacuum (below 5microns) and the monomeric fraction is calculated from the weight ofproduct distilling at 155C., the dimeric fraction calculated from thatdistilling between 155C. and 250C, and the trimeric (or higher) fractionis calculated based on the residue. When the gas-liquid chromatographytechnique is employed, a portion intermediate between monomeric fatacids and dimeric fat acids is seen, and is termed herein merely asintermediate, since the exact nature thereof is not fully known. Forthis reason, the dimeric fat acid value determined by this method isslightly lower than the value determined by the micromoleculardistillation method. Generally, the monomeric fat acid contentdetermined by the micromolecular distillation method will be somewhathigher than that of the chromatography method. Because of the differenceof the two methods, there will be some variation in the values of thecontents of various fat acid fractions. Unfortunately, there is no knownsimple direct mathematical relationship correlating the value of onetechnique with the other.

The preferred polymeric fat acid employed must have a dimeric fat acidcontent determined by gasliquid chromatography in excess or greater thanpercent by weight (preferably greater than 92 percent) and a ratio oftrimer to monomer (T/M) in the range of about 4-7 percent by weight withan intermediate content not greater than about 4.5 percent by weight anda T/M of at least about 5 percent when the intermediate content is above3 percent by weight. This latter limitation arises from the fact thatthe intermediate fraction lying between monomer and dimer functionallybehaves at least in part as a monomeric fat acid, experience indicatingabout 25 percent of the intermediate acts as a monofunctional material.Thus, the trimer content or T/M ratio must be higher as intermediatecontent is higher in order to compensate for the monofunctionalcharacter of the intermediate present in the larger amounts in order toprovide adequate melt viscosity properties.

The polyamides of this invention are preferably prepared by reacting thepolymeric fat acids with a diamine. Generally the polyamides areprepared by the conventional amidification procedures, usually heatingthe reactants to a temperature between and 300C, preferably 225250C.,for a time sufficient to complete the reaction, generally 2-8 hours.Essentially molar equivalent amounts of carboxyl and amine groups areemployed in preparing the polyamide. The resins may also include othercopolymerizing acid and amine components and the copolymerizing acids ordiamines employed may be a single diamine or a mixture of two differentcopolymerizing reactants. In addition, small amounts of monomeric,monocarboxylic acids may be present. With regard to any of the acidcomponents, any of the equivalent amide-forming derivatives thereof maybe employed, such as the alkyl and aryl esters preferably alkyl estershaving from 1 to 8 carbon atoms, the anhydrides or the chlorides.

The diamines which may be employed may be ideally represented by theformula where R is an aliphatic, cycloaliphatic or aromatic hydrocarbonradical preferably having from two to 40 carbon atoms. Likewise, R maycontain both aliphatic and aromatic hydrocarbon groupings. Illustrativepolyamines are ethylenediamine, hexamethylenediamine,tetramethylenediamine, and the like, bis (aminoethyl)benzene, cyclohexylbis(methyl amine), dimeric fat diamine, etc. The diamine may be employedalone or in mixtures of two or more. The most preferred diamines are thealkylene diamines having two to eight carbon atoms in the alkylene groupand mixtures thereof with dimeric fat amines.

The copolymerizing compounds commonly employed are aliphatic,cycloaliphatic or aromatic dicarboxylic acids or esters defined by theformulas:

R OOC COOR and where R" is an aliphatic, cycloaliphatic or aromatichydrocarbon radical preferably having from one to carbon atoms and R ishydrogen or an alkyl group, preferably having one to eight carbon atoms.Such acids include oxalic, malonic, adipic, sebacic, suberic and thelike. When copolymerizing dicarboxylic acids are employed with thepolymerized fatty acids, it is preferred that the carboxyl groups fromthe polymeric fat acids should account for at least 50 equivalentpercent of the total carboxyl groups.

In addition to the polyamide polymers described above, other polymershave been satisfactorily used within the scope of this invention. Theflexible copolyesters are applicable. These polyesters are preferablybased on dimer acids, isophthalic acids, terephthalic acids, adipic acidwith ethylene glycol or l,4-butanediol. The dimer acid is generally usedin a ratio of up to a maximum of about 70 percent of the terephthalicacid content. These copolyesters are prepared as disclosed in Example V.Other suitable thermoplastic polymers useful within the scope of thisinvention include the following: vinyl chloride/vinyl acetate copolymerssuch as a commercially available copolymer comprised of 84 percentpolyvinyl chloride and 16 percent polyvinyl acetate; thermoplasticpolyurethanes such as those obtained by reacting a polyether anddiisocyanate, e.g. the glycol of dimer acid and isophorone diaminediisocyanate in the presence of a catalyst, e.g. dibutyl tin dilaurate.Other thermoplastic polymers useful within the scope of this inventionwill be readily apparent to those skilled in the art. The

glycols of dimer acid can be prepared as disclosed in U. S. Pat. No.2,347,562.

When filament spraying the adhesive, the thermoplastic polymer isdissolved in a solvent which is capable of rapidly evaporating andsprayed from solution to form a fibrous mat. The solvents useful in thisinvention are those which dissolve the polymer resin and have anevaporation rate of less than 5.5, preferably less than 3.0. The termevaporation rate" as used herein is defined as the ratio of timerequired for a given volume of the solvent to evaporate at 7 3.5 i-2F.and 50:4 percent relative humidity when compared to the same volume ofdiethyl ether which is assigned the value of l. A suitable testingprocedure is given in the Paint Industry Magazine, Vol. 76, No. 4, p.15, April 1961. To determine whether or not a solvent would dissolve thepolymer, the mixture of solvent and polymer was placed in a conventionalpaint shaker for one hour of shaking. If at the end of that time, theresulting liquid phase of the mixture was not clear, the system wasdetermined to be incompatible. It has been found that chlorinatedhydrocarbon solvents with a suitable evaporation rate work mostsatisfactorily. Solvents can generally be classified into threecategories; very useful solvents having an evaporation rate of less than3.0, operable solvents having an evaporation rate of about 5.5-3.0, andunsitable solvents having an evaporation rate of above 5.5. Illustrativeof evaporation rates of some representative solvents are listed asfollows:

Group Solvent Evaporation Rate l Methylene chloride 1.8 Tetrahydrofuran2.0 Chloroform 2.2 Methyl chloroform l, l l -trichloroethane) 2.7

[I Methanol 5.2

III Ethanol 7.0 n. propanol 7.8

Various mixtures of solvents can be used so long as they fall within thesuitable evaporation rate. For instance, small amounts of solvents whichby themselves would be within Groups II or III can be mixed with largeramounts of Group I and still have an evaporation rate of less than 5.5.It is therefore possible to have binary solvent systems. Suitablemixtures include tetrahydrofuran with small amounts of methanol, andfluoronated hydrocarbons (Freon) and other commercial propellants withsmall amounts of alcohols which induce solubility and have the desiredevaporation rate.

When spraying the polyamide resins from the solvent mixtures asdescribed above, it has been found that the viscosity can significantlyinfluence the type of web effect obtained. Generally, the viscosity ofthe resin is a function of the molecular weight and is the determinantof solution viscosity and product performance. The following shows therelation of the spray solution viscosity ranges:

Low viscosity 0.5 10.0 centipoises Medium viscosity 10.0 65.0centipoises High viscosity 65.0 100.0 centipoises Generally, a lowviscosity, e.g., 0.5-10.0 cp., produces a finely divided fibrous spraywhich is solvent saturated when airborne in the spray. Since a largepercentage of the atomized solvent is carried to and deposited on thesubstrate, the short resin fibers are partially redissolved giving a matsurface of unusual continuity. Generally, it is necessary to obtain anoptimum balance between solids content of the solution, discharge rateand solvent evaporation rate. it is also known that as the viscosityincreases, the solvent solution containing the resin becomes moredifficult to discharge and atomize and the resulting fibrous texture ofthe mat eventually resembles a spattering of individual globules.Likewise, the bulk density of the mat increase with an increase insolution viscosity. Also, as is shown in the examples, the higherviscosity resins result in greater tensile strength and betterelongation.

When spraying the copolyesters, the above solvent requirements are alsoapplicable. Suitable solvents include chloroform, methylene dichloride,and blends thereof.

Various methods of spray application have been found to worksatisfactorily. These include air gun spraying, aerosol spraying, airbrush, and other conventional methods of spray application. The optimumspraying conditions can be easily obtained by simple spray testingtechniques. An important element for an aerosol application is properselection of the valve assembly. A useful nozzle is a Model 103Newman-Green spray head having a 0.055 inch slot and a 0.060 inchorifice and a vapor tap hole in the capillary dip tube enlarged to 0.050inch. Other methods of application will be readily apparent to thoseskilled in the art.

As indicated above, various polymers can be utilized in the formation offibrous mats which are used as fabric adhesives. They are characterizedas having a degree of solubility in organic solvents sufficient to beapplied by the spray method. The mat thus formed may be sprayed directlyon the fabric or on a releasing surface from which the fibrous mat maybestripped as a self-supporting fibrous web or mat. in general, thepreferred type of polymers are those which have low tensile modulus andresistance to laundering coupled with good color and high peel strength.

This invention will be further illustrated and is not intended to belimited by the following examples.

Example I 36 M (Monomer) i6 1 (Intermediate) )6 D (Dimer) k T (Trimer)Equivalent Wt.

A color remover, a 10 percent solution of phosphoric acid in an amountof 150 grams, and Antifoam A (Dow-Corning as a 1 percent solution inxylene in an amount of grams was added to the reactor. The abovereactants were heated to 250C. over a period of 3 hrs. and thetemperature was held at 250C. for 4 hrs. The resulting polyamide had thefollowing analysis:

Meq. acid/kg.

Meq. amine/kg. 122.3 T.S. (Tensile Strength) 4016 psi Y.S. (YieldStrength) 289 psi 56 Elongation 653 M.l. (Melt index at 175C.) 5.5

A solution containing the above resin was prepared by mixing thefollowing:

Parts by Weight Polyarnide resin 13.6 Methanol 13.6 Dichloromethane 59.2Tetrahyd rofuran 1 3 .6

This solution had a Gardner viscosity of A. The solution was charged toa DeVilbiss spray gun and the pressure set at 30 psi. The mixture wassprayed onto a Teflon coated glass cloth. The evaporation rate of thesolvent resulted in the polymer being deposited on the cloth as afibrous, discontinuous, porous mat. The fibrous mat was cut into /4 inchstrips and used to bond 10 inch zippers to a medium weight wash-and-wearfabric of 50 percent cotton and 50 percent polyethylene terephthalatepolyester fiber (Dacron). The fibrous mat was placed over the fabric andthe zipper tapeplaced on top of the fibrous mat. The fabrics were thenbonded with a household iron at a temperature of 280F. for 30 Seconds.No showthrough was evident, The peel strength of the bond was thendetermined in the following manner.

The top end of the zipper was pulled by hand to obtain a tab to insertinto the jaws of an lnstron tester. The corresponding tabs of thewash-and-wear fabric was inserted in the other jaw of the lnstron testerand the zipper was stripped from the fabric at 2 inches/minute. The peelstrength which resulted was 4.65 lbs/in. and the shear strength was 41.8psi with percent fabric failure.

Example 11 Example Ill A polyamide polymer was prepared as follows. Thefat acid dimer in an amount of 183.2 lbs. was reacted with 55.0 lbs. ofhexamethylene diamine. The above reactants were heated to 250C. over aperiod of 1 hrs. The temperature was held at 250C. for 7 k hrs. Theresulting polyamide had the following analysis:

Meq. acid/kg. 37.1 Meq. amine/kg. 6.7 Ball 8L Ring Softening Point 103C.

Two solutions were prepared as follows:

Solution 1:

Parts by Weight Poly-amide Resin from Examplel 13.6 Methanol 10Dichloromethane 59.2

The two solutions were then blended in an amount of 67 parts by weightof Solution 1 and 33 parts by weight of Solution 2. The blend was ahomogeneous, clear, and mutually compatible mixture. The solution waslightly sprayed as in Example I to form a discontinuous mat of randomlyarranged fibers on the back side of a flower pattern lace applique. Thelace applique was a very open, delicate design prepared on anembroidering machine. The applique with the adhesive mat was then placedover a knit nylon tricot so that the adhesive was in contact with thetricot. A flat iron set at 350F. was placed over the area to be bondedfor seconds. The lightly sprayed applique had a pee] value of 2.0lbs/in. The procedure was repeated by spraying a medium weight of thespray to the lace applique. After applying the applique as in thisexample, the applique had an average peel value of 5.0 lbs/linear inch.

In a non-uniform surface such as lace and appliques, peel values mast betaken as a measurement of a number of specimens because of the widevariation from one point of the applique to another. The values givenabove represent the averages of several measurements of peel value fromseveral sections of the bonded specimens. The above bonds demonstratedgood hand and the fibrous mat after bonding did not leave anyshowthrough in the openings in the lace structure. This is in directcontrast to extruded film which leaves a shiny resin film showing in theopenings of the lace. 1n the application of lace or appliques tolingerie type material, the fibrous mat has the advantage of disap'pearing after bonding and of giving a much more flexible hand to thebonded area.

Example IV This example will illustrate the relative efficiency ofbonding fabric with a discontinuous fibrous mat as compared to extrudedfilm. A section of the sprayed mat from Example 1 was cut into a stripof adhesive of 1 in. by 6 in. A film 5 mm thick was extruded from theresin of Example I in a conventional extruder. The film weighed 0.275grams and was 1 r in. by 6 in. long. The film and the mat were each usedto bond a cotton label to a 100 percent pima cotton fabric of'a weightsuited for production of a mens shirt. The adhesive was placed on thecotton fabric and the label placed over the adhesive. The labels werethen attached at 275F. at 150 psi pressure with the results as indicatedbelow.

This example demonstrates that the fibrous mat is more efficient perweight of polymer used than is the polymer in the form of an extrudedfilm. Thus, the

discontinuous, porous adhesive mat is superior to an extruded adhesivefilm.

Example V An ethylene glycol polyester was prepared'from a hydrogenateddistilled dimer acid and terephthalic acid. The dimer acid had thefollowing properties:

% M 0.5 %l 4.2 D 95.1 T 0.2 Acid value 0.3 IV 8.0 Sap. value 189.2

The polyester was prepared by heating together 401 grams of hydrogenateddistilled dimer methyl esters, 404 grams of dimethyl terephthalate, 378grams of ethylene glycol, 0.20 grams of zinc acetate times 211 0, and0.24 grams of antimony trioxide at up to 240C. until 234 ml. of methanolhad been evolved. Vacuum was then applied while the temperature wasmaintained at 260C. for 2 hours. The product was discharged. A polyestersolution was then prepared as follows: Solution A: Weight Parts byWeight Polyester Methylene dichloride Gardner viscosity A-4 (0.22Stokes) Solution B:

Polyester 12.5 Chloroform 87.5 Gardner viscosity A (0.5 Stokes) SolutionC:

Polyester 10 Chloroform 16 Methylene dichloride 74 Gardner viscosityEach of these solutions was sprayed as in Example I to form adiscontinuous adhesive mat. The mat was then used to bond a pima cottonat a bonding temperature of 350F. and a dwell time to achieve optimumbonding for a given weight of mat. 1n each case, 3 sq. in. of the matwas tested. The results are summarized in the table below:

A polyurethane was obtained by reacting the glycol of dimer fatty acidwith isophorone diamine diisocyanate in an excess of about 1 percentalong with a catalyst, dibutyl tin dilaurate. The mixture was blendedfor 10-15 min. and then placed under vacuum for 5 hrs. in a temperaturevarying from 80108C. The thermoplastic polyurethane resulting from thistreatment was dissolved at 4.4 percent solids content in methylenedichloride. The solution was sprayed at 45 psi to form a fibrous matfTwomats were obtained by spraying for different lengths of time, one matweighing 0.35 g./sq. in. and another mat weighing 0.070 g./sq. in. Themats were dried by allowing the solvent to evaporate at roomtemperature. The thermoplastic polyurethane mat weighing 0.35 g./sq. in.was then bonded to a fabric blend of 65 percent polyethyleneterephthalate polyester/35 percent cotton at 380F. and a home flat ironapplied to the bond with a force of 18 lbs/30 sec. dwell time. The bondswere made by placing a layer of fabric, then a layer of the fibrousweb,followed by another layer of the fabric, and bonding as indicated above.The bond thus formed had good hand and exhibited no showthrough. Thepeel strength of the bond had a value of 3.22 lbs./linear-in. whentested on the lnstron tester.

Example Vll A thermoplastic polyurethane was prepared by reacting theglycol dimer fatty acid with 2,2,4-trimethyl hexamethylene diisocyanatein an excess of about 2 percent of the diisocyanate. The catalyst wasthe same as in Example VI. The materials were reacted as in Example V1for 2 /4 hours at 80C. A solution of 7.8 percent of the polyurethane inmethylene dichloride was. sprayed under an atomizing pressure of 45 psi,thereby forming a fibrous mat. The fibrous mat produced had a density of0.75 g./sq. in. The mat of this example was bonded as in Example Vlexcept that the flat iron was set at 350F. The bond produced a very goodhand and had a peel value of 8.45 lbs./in. The bonds of Examples VI andVII appeared to be very flexible and could be stretched without parting.

Example Vlll A commercially available vinyl chloride/vinyl acetatecopolymer, VYHH, which consists of 84 percent polyvinyl chloride and 16percent polyvinyl acetate was dissolved in methylene dichloride at 16.2percent solids content. The mixture was sprayed at 40 lbs./sq. in. andformed a fibrous mat of very short fibers. A mat weighing 0.057 g./sq.in. was then bonded as in Example VII and had a bond value of 5.06lbs/linear in. When the bond time is reduced to 15 sec., the bond valuewas 3.06 lbs./sq. in.

Example lX and exhibited poor hand. The 15 sec. dwell time bond had abonded value of 5.78 lbs/linear in. and the 30 sec. dwell time had abonded value of 6.39 lbs/linear I The bonded seams have held up toconventional type laundering. lt is understood that garments having laceappliques attached thereto do not generally require the same launderingconditions that would be encountered in such things as mens shirts,childrens playclothes,

etc. The method of bonding as disclosed herein wouldbe very suitable forattaching crocheted or embroidered decals or appliques to fabrics of alltypes.

In addition to the advantages derived in the open weave bonding, theadhesive when applied as disclosed herein produces a greatly enhancedhand of the bonded area.

The bonded area when prepared as disclosed herein produces a finalproduct that is porous in nature and allows for normal breathing in thegarment. Since the mat produces a non-uniform surface, the area to bebonded requires less pressure to be applied to the surface of the fabricthen the conventional film adhesives. Light pressure is especiallyadvantageous for bonding delicate fabrics and appliques to all types offabrics. Further embodiments will be readily apparent to those skilledin the art.

The embodiments of the invention in which an exclu v sive property orprivilege is claimed are defined as follows:

discontinuous fibrous thermoplastic adhesive mat comprised of a. placingthe fibrous adhesive mat on a fabric surface, thereby leaving onesurface of the adhesive exposed,

b. placing a fabric on the exposed side of the adhesive,

c. heating the fabric and adhesive mat to a sufficiently hightemperature and for a sufficient period of time to bond the fabricsurfaces together wherein the thermoplastic adhesive is a polyamide of apolymerized fatty acid having a dimer content of greater than percentand a diamine of the formula H NRNH, wherein R is an aliphatic,cycloaliphatic or aromatic hydrocarbon radical of two to 40 carbonatoms.

2. The method of claim 1 wherein the diamine is an alkylene diaminewherein the alkylene radical is two to eight carbon atoms.

3. The method of claim 2 wherein the diamine is hexamethylene diamine.

4. The method of claim 1 wherein the polymeric fat acid is a polymerizedmonocarboxylic acid having from 16-24 carbon atoms.

5. The method of claim 7 wherein the monocarboxyl ic acid has 18 carbonatoms.

6. The method of claim 1 wherein 25-75 carboxyl equivalent percent ofthe polymerized fat acid is a copolymerizing acid of the formula HOOCR-COOl-l wherein R is an aliphatic hydrocarbon radical of six to 12 carbonatoms.

1. A method of bonding fabrics with a porous,

1. A method of bonding fabrics with a porous, discontinuous fibrousthermoplastic adhesive mat comprised of a. placing the fibrous adhesivemat on a fabric surface, thereby leaving one surface of the adhesiveexposed, b. placing a fabric on the exposed side of the adhesive, c.heating the fabric and adhesive mat to a sufficiently high temperatureand for a sufficient period of time to bond the fabric surfaces togetherwherein the thermoplastic adhesive is a polyamide of a polymerized fattyacid having a dimer content of greater than 80 percent and a diamine ofthe formula H2N-R-NH2 wherein R is an aliphatic, cycloaliphatic oraromatic hydrocarbon radical of two to 40 carbon atoms.
 2. The method ofclaim 1 wherein the diamine is an alkylene diamine wherein the alkyleneradical is two to eight carbon atoms.
 3. The method of claim 2 whereinthe diamine is hexamethylene diamine.
 4. The method of claim 1 whereinthe polymeric fat acid is a polymerized monocarboxylic acid having from16-24 carbon atoms.
 5. The method of claim 7 wherein the monocarboxylicacid has 18 carbon atoms.